<script src="vue.js"></script>
<div id="app">
    <div v-bind:class="{box}">我是box
    <div v-bind:class="{inner}">我是inner1</div>
    <div v-bind:class="{inner}">我是inner2</div>
    </div>
</div>
<script>
    var vue=new Vue({
        el:'#app',
        data:{
            box: 'box',
            inner: 'inner'
        }
    });
</script>
<style>
    .box {
        background-color: rgb(167, 14, 197);
        width: 100%;
        height: 100%;

    }
    .inner{
        background-color: blue;
        width: 80px;
        height: 100px;
    }
</style>